After reaching out to a couple of people I'm happy to report that all agreed the dink is not a big deal, and it certainly doesn't warrant the tube being replaced.
So I'm going to send it to
@danson67 who will roll the high spots out, before filling what remains of the dent with silver solder. Having seen some of his handiwork I'm very grateful that he's able and wiling to do it.
After that it's going straight to Mercian for a repaint, they will do their best to match the colours and recreate the decals as accurately as possible. I've had a frame painted by them in the past and know their work to be of the highest quality.
With that small bump in the road negotiated the project goes on. The forks are currently dismantled prior to a service and upgrade.
The chainrings are off to be re-anodized. The seatpost is a tricky one, anodizing means losing all the laser etching, so I'm looking at some mickey mouse solutions, including permanent marker and nail varnish as I only really need to tidy up about an inch or so of the least worn area to make it look new when fitted.
Uncracked Gripshift Xrays are inbound, as are boots for the forks. I still need a Roberts stem (placeholder stem has been primed and is curing in the drying room) and a 95 Flite, although I have 3 flites from different years, as well as a couple of nice alternative saddles date stamped 1995, so like the tyres there may need to be a common sense compromise there.